Recurrent Symptomatic Cage Migration After Minimally Invasive L4-5 TLIF

A 70-year-old man presented with severe lower-back pain and left L5 radiculopathy that was resistant to all forms of conservative treatment. Imaging showed a grade 1 unstable degenerative listhesis at L4/5 that resulted in severe left lateral recess stenosis. To this end, he underwent an uneventful minimally invasive L4/5 unilateral transforaminal lumbar interbody fusion (TLIF), and he was discharged 3 days later with complete relief of leg pain. But 2 weeks later, he presented to the emergency room with a recurrence of severe left leg pain. A plain X-ray obtained in the ER showed a displaced interbody cage (backout). The patient underwent revision surgery, where the cage was removed. A larger cage was reinserted, and right-sided pedicle screw and rod fixation was performed. This resulted in complete pain relief until 2 weeks later, when the patient experienced yet another recurrence of cage migration. This time, the cage was removed, and the interbody space was successfully impacted with a bone graft. Since then, he has been pain-free over a 6-month period. The possible reasons for cage backout and strategies to prevent it are discussed.